Adjunctive lipid lowering therapy in the era of surrogate endpoints

Statins have been shown to reduce cardiovascular events. However, despite widespread use of statin therapy, residual cardiovascular risk remains, and this has left clinicians searching for an effective adjunctive therapy to optimize lipid profiles and reduce risk further. Given the cost and duration of large event driven trials, adjunctive lipid lowering therapy options have largely been evaluated through surrogate measures of atherosclerosis, making clinical practice decisions regarding combination therapy difficult. Two common approaches that have been evaluated almost entirely by surrogate outcome trials include the addition of ezetimibe or the addition of niacin. Our article attempts to place these surrogate end point trials in their proper context, providing clinicians with a practical approach to making clinical practice decisions regarding adjunctive therapy in the absence of clinical outcomes data. Although definitive changes to lipid lowering guidelines should be based on clinical outcomes trials, in the absence of clinical outcomes data, it is reasonable to make individualized clinical practice decisions on the basis of surrogate measures of disease as long as there is corroboration among the effect on atherosclerosis and lipid parameters as adjunctive therapy, and clinical outcomes as monotherapy. Given that niacin fits these criteria, it seems prudent to support the use of niacin as adjunctive therapy in combination with maximally tolerated dose of statin in patients with low high-density lipoprotein-cholesterol and known coronary artery disease. Three ongoing clinical outcomes trials evaluating niacin and ezetimibe in combination with statin will provide more definitive word regarding the safety and efficacy of these agents as adjunctive therapy.